const baseURL='/';
const headers={
  'Accept': 'application/json',
  'Content-Type': 'application/json'
}
function json2url(data){
  //{a：1,b:2}  =》 a=1&b=2
  let arr=[];
  for(let name in data){
    arr.push(name+'='+data[name])
  }
  //[a=1,b=2]
  return arr.join('&');
}
function http({url,data={},method='get',params={}}){
  if(!url)return;
    if(sessionStorage.getItem('token')){
        headers['token']=sessionStorage.getItem('token');
    }

    if(method.toLowerCase()=='get'){
        return fetch(baseURL+url+'?'+json2url(params)).then((res)=>res.json());
    }else{
        return fetch(baseURL+url+'?'+json2url(params),{method,headers,body:JSON.stringify(data)}).then(res=>res.json());
    }
}
export default http